Increased concentrations of plasma lactate predict pathologic dependence of oxygen consumption on oxygen delivery in patients with adult respiratory distress syndrome

Abstract

We asked whether increasing systemic oxygen delivery by blood transfusion could identify pathologic dependence of oxygen consumption on oxygen delivery in patients who have adult respiratory distress syndrome (ARDS) with and without increased concentrations of plasma lactate. Twenty-four ARDS patients were divided into normal (n = 11, lactate ≤ 1.8 mmol/L) and increased (n = 13, lactate > 1.8 mmol/L) plasma lactate groups. After transfusion of two units of packed red blood cells, oxygen delivery index increased significantly in both the normal and increased plasma lactate groups. In the increased plasma lactate group, this was associated with a significant increase in oxygen consumption index and an unchanged oxygen extraction ratio. In contrast, in the normal plasma lactate group, oxygen consumption index did not change from the baseline value and the oxygen extraction ratio decreased significantly. We conclude that increasing systemic oxygen delivery by blood transfusion identifies pathologic dependence of oxygen consumption on oxygen delivery in patients who have ARDS and increased concentrations of plasma lactate.